Black walnut and gluing

[cowboy1296]

I have a furniture maker make my planks for me out of black walnut. Initially he used titebond III but we were having problems with glue failure and he went to titebond II. However we continue to have the same problem with failure. The pictures will show the failure of the glue. There maybe some uneven pressure applied on the plank from the clamps but the glued up part should be the strongest part of the board or at least I thought so.

First question: After forcing some glue or exoxy Into the opening how do I clamp a round plaque?

Second question: Since this has happened several times before how do we prevent it.

Thanks in advance.

[Bob Eustace]

Tricky one Rick. We swear by Titebond 3 despite it being dearer plus it gives a longer set up time. Never had a failure on the glue line. We are using it in the mountains with temps below 10 degrees C. We compensate for this by clamping 48 hours and keep the bottle warm. Why dont you try jointing a few bits yourself. Your supplier might be glueing straight off the saw maybe???

[wberminio]

It could be that the boards may have a snipe at the end from the jointer,
That could be putting stress on the joint and forcing it open.
Make sure the joints are tight before gluing.
Forcing them tight with clamps will not work no matter how good the glue.
Also are you using kiln dried or air dried wood?
If air dried,there maybe too much moisture in the wood.
Should be about 6-9% moisture.
I wouldn't use air dried lumber unless I was really sure on the moisture content

Erminio

[bob_reda]

I went through about 2000 board foot of black walnut in the last two years. Never had a glue failure on the line. I would agree with the snipe and trying to force it close. If you think moisture is the problem, go with gorilla glue,

Bob

[Ajcoholic]

Dont blame the glue... I have used pretty much every major brand of PVA on the market in the past 20 years - even the lesser expensive glues are stronger then the wood, the key being in a properly prepared joint.

That looks to me like it might be un-aclimatized wood (too high moisture content perhaps), or as suggested glued up under too much stress and unclamped too early.

Ive been using TIII exclusively going on 4 years now and processed probably 20,000+ board feet of hardwood (including a lot of walnut). The only time I have had issues on the ends of the boards opening on the joints (very few) is when I bring in lumber from storage, in the winter, and dont let it sit for a few days before I start processing it. Its going from a MC of 6% to 8%, to several percent drier in the winter.

If there is a snipe, you would be able to see it clearly. You cannot "clamp" that out of hardwood.

The other thing as I mentioned is that perhaps the clamps are being take off too soon. Or, a starved glue joint (not enough glue, or too high clamping pressure).

AJC

[Ajcoholic]

First question: After forcing some glue or exoxy Into the opening how do I clamp a round plaque?


You have to make up a caul in the shape of the disk - leaving the outer shape square/rectangular.

[knight_toolworks]

gorilla glue would not do any better and tends to not work as well. It used to work much better then it now does.

[bleeth]

It's the boards moving naturally from temperature and moisture changes and there really isn't much you can do unless you resaw your pieces smaller first and then glue them together. Western Walnut definitely will tend to do this when you glue two thick and wide pieces together. You may have a shot at success if you spline them together.

[waynelocke]

I agree that it may be a moisture issue because the ends will give up moisture first and could cause this. Do they all do this? My best guess would be that the boards are not properly jointed and they compensate with clamps to pull the ends flush and very quickly have this problem.

[cowboy1296]

It happens at least 50 percent of the time recently. I am going to take yalls ideas to my plank maker and we will go from there.

For a fix on the plaque which seems strong enough, I did force some titebond down inside of the opening. Not even sure that its needs it but I might follow up with a tiny amount of wood filer.

[bleeth]

Try mixing some fine walnut sawdust with your titebond and use that instead of straight titebond next time. Much stronger and eliminates the need for wood filler. Just over fill a little and sand when dry.

[Ajcoholic]

It's the boards moving naturally from temperature and moisture changes and there really isn't much you can do unless you resaw your pieces smaller first and then glue them together. Western Walnut definitely will tend to do this when you glue two thick and wide pieces together. You may have a shot at success if you spline them together.

There is a lot that you can do. Check the moisture content of the wood, monitor the relative humidity in your shop, check tables for where the wood should be and let it acclimatise before you glue up the panels.

I work with a lot of solid wood per year (10 to 15 thousand board feet per year) and I almost NEVER have these issues. When I do, I can always trace the issue back to something either I did wrong, or my lumber arrived from the dealer improperly seasoned (which is why everyone who works with solid wood should own and regularly use a moisture meter)

AJC

[feinddj]

The woodturner that I share my shop with uses a rachet strap without hooks. just the loop to clamp rounds. Also try shrink wrap. you can start it and each wrap will tighten as you pull it round.

David

[genek]

Moisture in wood or too dry of wood can be a major problem.
When I bring in wood from my suppliers I check the Moisture content prior to accepting the load. I have had the delivery trucks to let the wood sit outside uncovered and be rained on. When I bring the load into the shop, I allow the wood to adjust to my shops humidity. I like my wood to be around 8%. I will reject any wood that is over 16%. A good protimeter (moisture meter) is well worth the investment. I glue up walnut almost every day. I glue walnut to other woods like maple, and cheery. Like Mr. Coholic said there is a lot one can do to prevent this from happening.

I would love to see that joint sawed off so that I could see the edges where it separated. Failures in joints can be and will be caused by the following.
1. not enough glue (glue was not spread evenly.)
2. glue edges not square
3 under clamping in pressure and in time.
4. over clamping
5. high moisture content
6.excessive water used to clean up glue squeeze out.
7. watered down glue.
8. old glue
9. to much glue and not enough clamp pressure.
10. wood not evenly dry.
11. voids in glue.
12. oil in certain woods.
these are just a few reason that wood will separate at the joint.


Again I would love to see a clean picture of that joint (where the glue should have been.) This will tell me if the wood failed, glue failed, or improper joint etc.

I would be worrying about all of the products, if you are getting 50% failure, You will more than likely have even more failures after it leaves your shop.

A good glue joint will always be stronger than the wood itself and the wood should split or break before a joint separates

[gc3]

Titebond III was designed to pass the ANSI/HPVA Type I water resistance specification, which doesn’t entail great water resistance so much as high temperature water resistance. This makes it uniquely well suited to applications where steam or boiling water may be encountered, the best example being cutting boards. Despite the fact that no one recommends it, when your cutting board finally runs through a dishwasher it won’t delaminate if you used Titebond III.

Under typical environmental conditions Titebond II and Titebond III are equally resistant to water. However, Titebond III exhibits greater thermal plasticity, which is a technical way of expressing that it loses more strength as temperature increases. Since all PVA adhesives form a plastic film when dried this plastic will effectively melt once a sufficiently high temperature is reached. Titebond Original and Titebond II lose about 50% of their strength at 150

[cowboy1296]

I am going to share with the furniture maker all that you have said on here. I did check the moisture of the boards just last night and my little no name meter says 5-6 percent. I still have the boards where the glue failed and I will post a photo later today of the failure joint.

[waynelocke]

Do you supply the wood or does the furniture maker? If he does, you should be able to hold his feet to the fire whatever the cause. He would then be unequivocally responsible for the failures and also better able to control the finished product. I always prefer to secure the materials myself.

[hh_woodworking]

The only time I see failure in glued planks is when the students either doesn't have a good straight joint, or the student over clamps the wood and squeezes the glue out of the rest of the joint. Our requirement on gluing is also no boards over 4" wide are glued together, along with grain flipping.

[genek]

The only time I see failure in glued planks is when the students either doesn't have a good straight joint, or the student over clamps the wood and squeezes the glue out of the rest of the joint. Our requirement on gluing is also no boards over 4" wide are glued together, along with grain flipping.

Mr. Harrall I am glad you mentioned about over clamping most think I am joking about over clamping. I just sent you a private message also.

thanks for posting.

[cowboy1296]

Here is a picture of the ends of the black walnut where the glue failed. Can anyone see what might be a problem.

[steve_g]

Wow... I did a "glue testing" science project with my 6 year old grand son... In our testing even with the "cheap" glues the wood failed before the glue did! Judging by the reticulation pattern of the glue, it looks like inadequate clamping, or the clamps were released before the glue was set. Perhaps "set" time was affected by thinned or old glue.

SG

[genek]

Mr. Glassel I agree with you. I would have your supplier check his tools for square.

The air bubbles indicate that the wood was not clamped tight. With the rest of the glue up holding. I think it has been improperly edge planned, possible was just sawed and not planned at all or it has snipe on those ends. if he is using air clamps he needs to check pressure on his clamps. I had one over clamping and I ended up with a week joint. This one is no over clamped.

[jTr]

I agree with Steve - those lines indicate bubbles - all the white areas are where glue bridged the gap from board to board and made contact with the intended mating surface - only about 5-10% of surface area. All dark glazed areas are where no continuity of flow occurred from board to board.

Amount of glue, clamp pressure and snipe are what I would consider as factors that caused the failure.

No offense, but I would not consider the wood or the type of glue to be contributing factors.

If at all possible, try to glue up enough material to cut off 2-3" from each end of your targeted work piece, thereby avoiding the most problematic areas of a glued lamination since this is where the snipe issues reside. If material limitations do not permit this approach, closely inspect the jointed surfaces to be glued for snipe or other irregularities by holding near a raking light source at a low angle for easier visual analysis.

Sorry about your troubles, and hope it works out in the end.

jeff

[Brian Harnett]

There are lots of reasons for failure but Gluing from a proper saw is not one of them, I have had more issues from joints off a jointer than a properly set up saw.

High pressure in an epoxy joint will have failure as the epoxy soaks and causes a dry joint before cure.

Too little pressure on PVA glue or taken out to early will have issues, as too much pressure, moisture,content,temp, or whatever just to throw that in.

[cowboy1296]

I did contact Titebond this morning and sent them the picture and their gut feeling is it is a clamping issue. All of your thoughts have been passed on to the furniture maker who makes the planks. Thanks.

[cowboy1296]

After letting my plank maker read the remards he has added time to his clamping. The last plank came out with no issues and lets hope that it stays that way. Thanks for the help